Powder coating problem

[coach New User Find all posts View Profile Close coach]

I've been powder coating my engine parts with a poylester coating and wiped the finish with a little laquer thinner and had a dulling reaction to the finish.I tried carb cleaner with the same results.Dot 3 brake fluid, ant-freeze had no effect on the finish.I thought this type of powder would be ok for this purpose.I didn't clear coat.Am I doing something wrong or is this normal.I wanted to do a carb.Thanks for your opinons.coach

[FSTFBDY Amateur Metal Finisher Find all posts View Profile Close FSTFBDY]

Re: Powder coating problem

sounds like its not fully cured to me. They make a cure kest kit that you swab the part with a q-tip. back and forth so many times. If the powder breaks down as you described its not fully cured.

[callmej75 Amateur Metal Finisher Find all posts View Profile Close callmej75]

Re: Powder coating problem

Or another way you could check for full curing is the MEK rub. Take a rag and dip a small part in MEK and rub it back and forth applying light pressure maybe 6-10 strokes. No powder wiping off means you have cured well.

[blackcamaros New User Find all posts View Profile Close blackcamaros]

Re: Powder coating problem

I just wiped something this morning with laquer thinner and had the same result. Can the part be put back in the oven and cured longer, or what is the fix for a part that you have tested and is undercured?

[callmej75 Amateur Metal Finisher Find all posts View Profile Close callmej75]

Re: Powder coating problem

If it was me...I would try to cook it for maybe 5-8 minutes more. If that don't cure it then do a bunch of sample panels and mark them at different curing times. Better yet, get a infrared thermometer and test out a part by putting it in the oven and see how long it takes it to heat up to the temp at what your powder says to bake at. Thats when you start the time specified for the powder. When the part reaches that temp is when the powder starts to cure.

[speeddemonrodsteration New User Find all posts View Profile Close speeddemonrodsteration]

Re: Powder coating problem

are you sure its a case of under-cure? I've done pieces that had plenty of cure time- they aren't affected by Gasoline, MEK, paint prep cleaner, ect. everything except for Aircraft remover (of course) and lacquer thinner- after all isn't powder coating just a different style of paint? maybe I'm wrong.